Analysis of the Development of Flood on Basin of the Stream San Pedro Uberlândia - Mg (PAP014778)
Ana Clara Mendes Caixeta, Lucca Alfinito Felippe, Luiz Nishiyama
The rapid growth of Brazilian cities after the 1970s was a result of rural exodus and it generated a profound modification in the structure of the urban land and made alteration in hydric dynamic. However, one must consider not only the modification of the soil by the waterproofing point of view, but also the modification of the soil by the perspective of the growth of cities without adequate planning. Another aspect that deserves attention is the urban climate. This one causes alterations in atmospheric dynamics and it results in episodes of concentrated precipitations. Consequences of this interaction between meteorological and hydrological nature factors can be proved by growth of flood events related to intense rainfall. According to Tucci (2009), he reports that the determination of maximum precipitations is one way of knowing the flood flow rates in a river basin. These elements, when conjugated, generate an increase of the flow and the velocity of a runoff and they are the main causes of Brazilian urban flooding. Thus, this work has as main objective correlating the historical of flooding in São Pedro Stream Basin in Uberlândia / MG to the extreme precipitations and to the disordered urban growth. The closed canalization of this Stream was held in 1980 because of the construction of Rondon Pacheco Avenue. In this study about floods in the San Pedro basin an ample research was carried out in three stages. The first one was to raise the most significant historical floods through a quest at Municipal Archive of Uberlândia, Municipal libraries, Federal University of Uberlândia and digital records available on the web. The second stage was the characterization of precipitation standard (intense rainfall and relatively short duration), during a historical series of 32 years (1981-2013) along, available at Climatological Station of the Federal University of Uberlândia. Until 2002 the pluviometric data were obtained by reading rain gauges. Thereafter, the data were obtained by pluviographs. The third stage was the characterization of standard urbanization in the area of São Pedro Stream basin, which has been increasing impermeable surfaces and, consequently, runoff. With the information acquired in three stages, it is presented the basis to carry out an analysis of the evolution of floods in the study area. According to the pluviometric data of UFU Climatology Station, the rain of 1986 resulted in a accumulated precipitation of 157.8 mm, which produced a situation of complete destruction of the existing gallery. However, one must consider that 27 years ago there were still considerable areas for infiltration of rainwater into the basin. Nowadays, the urbanization growth near the basin area is raising impermeable surfaces. Thus, the floods are becoming more frequent even with a precipitation of lower intensity, an example of this fact was registered in May 2013. Finally, it is emphasized that there is a complex interaction of factors that result in flooding in São Pedro stream basin. Only understanding these factors and their interaction will show a solution to this problem.